WHI Observational Study Suggests Increased Physical Activity
Reduces Breast Cancer Risk
NHLBI STUDY FINDS MODERATE PHYSICAL ACTIVITY PROMOTES WEIGHT LOSS
AS WELL AS INTENSE EXERCISE
Women trying to lose weight can benefit as much from a moderate
physical activity as from an intense workout, according to a new
study supported by the National Heart, Lung, and Blood Institute
(NHLBI), part of the National Institutes of Health in Bethesda,
MD.
Prior studies had focused on short-term weight loss. Data were lacking
about the optimal degree and amount of physical activity for long-term
weight loss.
The study–“Effect of Exercise Dose and Intensity on
Weight Loss in Overweight, Sedentary Women: A Randomized Trial”–appears
in the September 10, 2003, issue of The Journal of the American
Medical Association (JAMA).
The same issue of JAMA also includes an article on recreational
physical activity and breast cancer risk. The study, based on data
from the Women’s Health Initiative’s Observational Study,
found that increased physical activity was associated with a reduced
risk for breast cancer in postmenopausal women. Longer duration
physical activity gave the most benefit but the physical activity
did not need to be strenuous to reduce breast cancer risk.
The exercise dose and intensity trial involved 201 overweight but
otherwise healthy women ages 21-45. All received reduced calorie
meals in addition to being randomly assigned to one of four physical
activity regimens, which varied by intensity and duration. The regimens
consisted of either a moderate- or vigorous-intensity physical activity
performed for either a shorter (2 ½ to 3 ½ hours per
week) or longer (3 ½ to 5 hours per week) duration. The physical
activity consisted primarily of brisk walking, and the regimens
used about 1,000 or 2,000 kcal per week.
Women in all four groups lost a significant amount of weight–about
13 to 20 pounds–and maintained their weight loss for a year.
They also improved their cardiorespiratory fitness. However, the
amount of weight lost or fitness improvement was not different among
the four groups.
To arrange an interview about the physical activity and weight loss
study, contact the NHLBI Communications Office at (301) 496-4236.
To arrange an interview about the physical activity and breast cancer
study, contact the National Cancer Institute Press Office at (301)
496-6641.
NHLBI press releases, fact sheets, and other materials are
available online at www.nhlbi.nih.gov
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